An airbag module with the above-referenced characteristics is described in EP 0 838 377 B 1. Insofar as a rebound strap is located inside the inflatable airbag for the control of its inflation characteristics, the rebound strap will have a first shorter section, tensioned by the inflating airbag or the airbag portions moving in opposite directions at the start of the inflation process. Once the effective inflation pressure inside the airbag exceeds the predetermined breaking point of the first section of the rebound strap, this first section of the rebound strap will rupture, so that the airbag can be inflated until the second, longer section of the rebound strap is tensioned, wherein the length and location of the second section of the rebound strap inside the airbag determined the final inflated shape of the airbag.
The design of a two-section rebound strap described in EP 0 83 8 377 B 1 is characterized by the flat mid-section of the rebound strap, formed by an elongated cut of material, from which the two rebound strap sections of varying length and width originate on both sides. The mid-section of the rebound strap is attached to the one airbag portion, with the respective free ends of the first section and the second section of the rebound strap attached to opposite portions of the airbag. When the respective airbag portion, including the attached mid-section of the rebound strap and the attached ends of the two rebound strap sections, move in opposite directions during inflation of the airbag, the first shorter section of the rebound strap will be tensioned initially, and following the rupture of the first section of the rebound strap, the second longer section of the rebound strap will be tensioned, determining the inflated shape of the airbag.
The known airbag module, or more specifically the arrangement of the rebound strap inside the airbag, entails the disadvantage of requiring a complex cut of the rebound strap, characterized by three sections with varying geometrical specifications.
In addition, three seams each are required for the attachment of the mid-section of the rebound strap to the airbag portion, and of the two ends of the two sections of the rebound strap to the other portion of the airbag. Furthermore, two spatially separate sections of the rebound strap run through the airbag, which may lead to problems when folding or inflating the airbag.
Therefore, the problem of this invention is to design an airbag module with the above-referenced characteristics in such fashion that the cost of fabrication and attachment of a two-section rebound strap inside the airbag will be reduced.